Our current application of Heating, Ventilation, and Air-Conditioning systems (HVACs) is a crucial concern for our environment. HVAC systems are one of the largest contributors to pollution and greenhouse gases, and they consume exceptionally high levels of both electricity and fossil fuels. One can see the indications as to the extent of the strain HVAC systems place on our energy resources in the brown outs and rolling blackouts in the state of California in the early 2000s, which were caused primarily by electricity demands from air-conditioning units. Moreover, central heating accounts for 69% of the natural gas usage in the United States. Fortunately, there are, however, several excitingly innovative, energy efficient, environmentally friendly HVAC options available for consumers who are looking to reduce their energy bill and help save our natural resources.
One of the functions of AC units is to filter water vapor from indoor air. Before discarding the water vapor, more efficient AC units use the liquid water as a coolant to keep the unit at a safe operating temperature greenhouse air conditioner. In some high-efficiency, environmentally friendly AC units, rather than discarding that coolant after use, the unit is equipped to condense this moisture and reroute it back into the system as cooled water in order to be reused, creating a water vapor-coolant cycle.
Systems with programmable thermostats have been available for quite some time now. These thermostats are becoming more sophisticated with more functions and options to fit a variety of lifestyles and air treatment needs. The advantage with these systems is that you can set your thermostat to heat, condition, or ventilate the air on a need-only basis. Need-only basis air treatment is one of the easiest ways to drastically reduce your energy bills. In fact, this savings potential was largely the initial reason for developing programmable thermostats-the low environmental impact being only a fairly recent (though genuine) advertising point.
Another form of need-only air treatment is the Off-peak cooling systems (OPC), which uses the refrigerant-filled coils to cool water well below its freezing level during hours of low demand, to store this ice in this condition, and then to use the ice to remove thermal energy from hot indoor air during the day.
In order to obtain heat from the outside air, many air-conditioning units are capable of reversing the air-conditioning process. This form of heating is achieved via a heat pump. These types of air-conditioning units are often called reverse cycle air-conditioners. Reverse cycle air-conditioning systems tend to be more economical and practical, and, when used during the winter months for heating, these systems are vastly more energy efficient and environmentally sustainable than standard HVAC systems.
Freon is the most common refrigerant used in HVAC systems. Freon was developed by DuPont and is scientifically known as chlorofluorocarbon (CFC), with a subclass known as hydrochlorofluorocarbon (HCFC). CFC and HCFCs have unequivocally been proven to contribute directly to ozone depletion. Simpler compounds with similar thermodynamic properties that do not contribute to ozone depletion have been developed as environmentally safe alternatives to CFCs. Both the Montreal Protocol and the Kyoto Protocol have established guidelines against the use of CFCs. The European Union has already begun a phase out of CFCs, and, after extreme resistance, the United States signed an agreement to phase out CFCs by 2020. This agreement means that non-CFC HVAC systems will probably become standard code in the near future, and buildings with CFC containing HVAC systems will be no longer pass building inspection.